Fructose is a hexose. 'Hextose' refers to the number of carbonatoms
in the ring, in this case 6. Fructose is found in fruits and vegetables.
In many cases, the fructose we consume comes from corn syrup. Fructose
itself is twice as sweet as sucrose but has only half the calories (its
only half the sugar). Fructose also has the property that it is not
absorbed into the blood as quickly as other sugars, especially when there
is little glucose. This has significant implications for diabetics.

HO2CCH2C(OH)(CO2H)CH2CO2H
.
Try saying that three times real fast. Shoot, just try saying it three
times. However it is said, it is known for a 'tart' taste. This acid
is found in citrus fruits (and thus the name) and can be extracted by
adding lime (calcium oxide, not the fruit) to for calcium citrate.
Citric acid can also be obtained by fermenting glucose with the aid
of the mold Aspergillus niger or synthesized from acetone or
glycerol. Citric acid is also a key part of the critic acid cycle that
is one of the metabolic pathways responsible for releasing energy from
sugars, amino acids, and fatty acids.

If you've noticed, there is a fair bit of acids and forms of acids in
Tang. Thats part of what gives it 'tang'. Granted, its nowhere near
the point where it gets to eating away the paper cup you drink it out
of, however it is considered a 'bad' thing to have the flavor be one
that bites too hard or gives heartburn.

On the flip side, it is trivial to find too much information on the Vitamin C. Ascorbic acid is a water soluble vitamin that cannot be stored in the body - it gets constantly flushed out. For this reason, it is necessary to have a source of vitamin C in one's diet. This was often a problem with long sea voyages and lead to scurvy amongst sailors. The British Navy implemented a plan to bring along citrus fruits leading to the name 'limey' for their sailors which still sticks today. Another source of vitamin C that has come into vogue recently is that of wheat grass. Pine needles can also be a rich source of vitamin C, although much less appealing in taste.

Natural flavor - you see it everywhere. Even the Altoids tin that I have
lists 'natural flavor', and yet it is not well defined anywhere.
For example, the KraftFAQ says this about the "natural flavor" in
Caprisun:

The ingredient "natural flavor" is a fruit extract. For example, wild
cherry natural flavor ingredient would be wild cherry extract. The actual
natural flavor proportions are a trade secret of the flavor suppliers.

All these things we're mixing in don't naturally look orange. That is
the magic of artifical color. For the most part at this point, we've
got something that looks like a white powder. Make it orange, and keep
it orange when water is added. Though, I'm sure some kids would find
it neat to have something that started out blue and turned orange when
water was added it wouldn't really be that great of a hit.

Cellulose - recognize that '-ose'? Same as sucrose and fructose above, this is a sugar. However, Cellulose is not a simple, or even a disaccharide. We're talking hundreds or thousands of simple sugars joined together. The simpler the sugar, the sweeter it tastes to us - cotton does not taste that sweet. Cellulose is the building blocks of all plant fibers and forms the cell walls that encase each plant cell in a rigid skeleton.

Xanthan gum is another polysaccharide and has numerous uses from
lubricants to filler. Xantham itself is made from the bacterium
Xanthomonas campestris and is commonly found on plants in
the cabbage family. Xantham is resistant to many enzymes and thus
improves shelf life and is soluble in hot and cold water, and a wide
range of acidic and alkaline solutions and salt levels. There is also
a paper written on the effects of xanthan gum and the size of baked
cakes (Miller, R.A. and R.C. Hoseney. 1993. The role of xanthan gum in
white layer cakes. Cereal Chemistry 70(5): 585-588.).

Also known as Sunset Yellow FCF. This is an acid dye. Although it is
difficult to represent the color itself on E2, the colors associated with
Yellow #5 are close to that of 0xF47A05 and 0xFAC67F. This is the second
most widely
used coloring (after red 40) and may cause mild allergic reactions in
individuals who are aspirin-sensitive.

Another sunset yellow coloring. This one is a bit more touchy and it
causes tumors in the adrenal gland and kidney in lab animals. It is
also possible that small amounts of carcinogens may contaminate Yellow 6.
However, the FDA has concluded that Yellow 6 does not pose any significant
cancer risk to humans. What today doesn't cause cancer?

Niacinamide is a water soluble form of vitamin B3 (Niacin). The differences
beyond its solubility are not clear. Furthermore, I have difficulty
trusting all the claims made by various online health stores about the
differences between them. In the brief research done, the literature claims
daily allowance for adults to be 16 - 19 mg, while the health stores have
500 mg tablets. Whatever the case, niacin and niacinamide are components
in several metabolicenzymes. These vitamins occur naturally in
lean meat, peanuts and other legumes; and are often part of enriched
bread and cereal products.

Vitamin A is an important antioxidant and is used in photoreceptors.
A fat soluble lipid, Vitamin A is found in such places as
liver, egg yolk,
cream, and butter. It is also found in beta-carotene
(leafy green vegetables and yellow fruits and vegetables).
Vitamin A is critical to vision,
skeletal growth and reproduction along with the health of the skin and
mucous membranes.

Combined with phosphorous in the body, the B6 group of
vitamins help form the enzyme pyridoxal phosphate which is part of the
metabolism of amino acids, glucose, and fatty acids. Primary sources
of vitamin B6 are liver and organ meats, corn, and other
seeds.

Riboflavin is one of the components of respiratory enzymes in plants
and animals and is an important part of oxidation. The natural sources
of this vitamin are plant and animal tissue, milk, and organ meats.

Butylated hyrdoxyanisole -
Similar to citric acid, BHA is an antioxidant and helps preserve food
by preventing it from oxidizing. Oxidation is the process that ripens
fruits and vegetables, and eventually turns it rancid.